The investigator has now interviewed nearly 800 BLSA males with regard to their history of marriage and sexual activity. Two types of data analysis were undertaken during the year. First, subjects with a history of prostatectomy and their controls were compared on some 114 attributes relating to medical status, many aspects of marital and sexual experience, and numerous measures of cognitive and physioloic function. Findings indicated that unstable coital and marital relationships, differing rates of sexual activity, and sexual attitudes and reactions are apparently unrelated to the genesis of benign prostatic hypertrophy. The second analysis concerned the question as to why males vary widely in frequency of sexual expression. An examination of numerous individual attributes by means of an analysis of variance model revealed that 4 variables could explain 48 percent of variance in current rates of activity. The predictive value of each variable varied widely, however, when the model was applied to relatively young, middle-aged, or old subjects.